Sky surfer inspired plane...

Started by topalle, July 12, 2014, 06:26:42 PM

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Rajesh14305

@topale sorry to say that this plane is no more.i lost it when flying .it gavenose dive.btw i have that bottom piece.give me a minute

topalle

No worries...

BTW... I enquired about that aluminium railing...they sell mimimum 12 feet and nothing less than that...
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Rajesh14305

no  no .last time i bought 2meter alluminium channel at rs40

topalle

After rummaging through our store room I found a ~2 foot peice which I think will be enough...
I tried sticking it to the fuse using SR 998 but the joint is appearing very fragile... What should I do?
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girishsarwal

Srinivas...youcl could drill holes and use m3 bolts and washers to secure the frame... Don't overtighten though
gs

topalle

Trial with thermocol was good enough
After exchanging pms with lot of forum menbers, I made a thermocol wing which is light weight...
The present wing is of 1000 mm wingspan and 200mm chord....
covered with old dhoti of grandfather...
Its spar is hardwood beading 20mm...
extra spar is remaining on one side...
I'll chop that off after the wing dries completely...
Also I'm unhappy with the dhoti not sticking properly to the wing where it has overlapped several times...

I would like to thank shobhit sir for teaching me how to hand sand thermocol...
If he permits me I'll share his detailed pm over here...
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topalle

here are some pics...
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rcrcnitesh

Can't see the aerofoil properly.
Maker | Aeromodeller | Teenager

Rajesh14305

pour fevicol on the dhoti .and then spread it on that to thin layer.after drying it will harden ur airfoil.if u have hair dryer the blow it over the glue to dry.itwill hardly take 5 minutes to dry

topalle

the mistake I did was using lot of water...
Now I'll directly pour fevicol over it and try...

I cant feel the hardness of the wing right now...
If that trick doesn't work out, I'll use computer paper or tissue paper...
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topalle

Here are the pms sent by shobit sir to me...
sharing this in public interest...

pm no. 1

Dear Friend,
Well all you need is to take a wood block of maybe 3 inches width and about 12 inches long.  Say .5 in thick.  Make three such Blocks.  DO NOT use plywood or ply board as it will hurt your hand and fingers with the sharp edges of wood which are there.

Now stick sand paper of 120, 100 and 60 grit to these blocks of wood.  Use the sandpaper which comes on cloth strips of about 4 inch width.

Now cut your sheets of thermocol of the required size.  Make sure the wing sides have come out exactly same in size.

Now make the max camber line on both top and bottom surfaces.  If its a flat bottom one then it is needed only on the upper surface.

Next make place for the Training edge and the Leading edge on the thermocol for the wing.  I use a 10 mm sheet balsa for the LE and a 6mm sheet balsa for the TE.  generally the sizes are 10 x 10 mm and 6 x 20 mm for the TE.

Sand the TE as required in a wedge form.  Fix the LE to the place on the foam.

Now sand the entire wing by keeping the thermocol on a table taking care to leave the place thich enough for you to fix the TE and also make sure that you shape the LE as you sand the wing using a 60 grit sand paper.  DO not file to the exact size with this paper as it is very rough and tends to breast the thermocol at times.

Use 100 and 120 grit paper to smoothen the wing surfaces......

After smoothening the wings add the TE to its place.

Now use a knife and cut grooves for the spars.  I have used hard wood spars and also used balsa spars.  Make the grooves on the top and bottom surfaces and put spars on both top and bottom surfaces.

For making the wing dehideral use a a 6 mm plywood piece or a 6 mm hard wood beeding as the centerpiece.  make use it is right through the thickness of the wing thermocol and is at least 6 inches outwards from the centre into each wing.

Now once all this is done.  I cover the centre section with a glass fibre cloth and epoxy.... about one foot of the centre section on top and bottom of the wings.  This gives great strength to the wing.

Now you can cover the wing with paper OR masking tape and later use vinyl sheet for various colours..... or paint the paper using fevicryl colours....

You can similarly make ur aerofoils and fix them to the wing.  Cut out the place for the servo and fix it there.

Best wishes....
Shobhit

pm no. 2

Well...... good show..  I do not fix the spar earlier as probably because my wings are bigger i.e. the minimum span I have made in 3.75 feet and have been made of at least one inch thick sheet of foam.  ANyway will try fixing the spar earlier if needed the next time.  Also I prefer to use fevocol for all my general work and I use the fast setting epoxy only for the dehidral angles or places which need to be fixed in a few minutes.

ok... now for your answers.....

Wing tips.... ok.  If you feel that you are going to bang the glider far too often then you may use Balsa wood wing tips.  OR else... just cover it with computer paper ad fevicol....  Use a thinned fevicol (use water for thinning) to paste a wet computer paper where you want to give extra strength.  While it is wet rub the thinned fevicol all over the paper and let it dry....  

You may use computer paper to cover the entire wing for added strength. Fix it the way I have written above and the wing becomes very strong.  But make sure that your spars are sufficient to give the strength required to the wing.  

I generally use masking tape and then vinyl sheet to cover my wings.  But off late have made an aerobatic model where the wing is just covered with paper and nothing else (a 4 feet span symmetrical cambered wing).

Do not for get to paint your model with fevicryl colours.....

Happy building your model.

Shobhit




Thank you so much sir for your guidance... :hatsoff: :) :salute:
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wingmanbunty

EAT ,SLEEP , FLY

topalle

Tommorrow I'll continue work on this as there is a bundh called by SFI and PDSU
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topalle

This covering was not at all stiff...
Its also adding a lot of weight....
Removed this covering....

I tried heat shrinking packaging tape ( brwon colour)
Its not shrinking due to heat.... :)
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topalle

wing completed.... ;D
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Rajesh14305

if u are using normal thermocol there is another methord that u completely wet news paper wrapit around air foil neatly then give fevico0l coating inside and out side

Rajesh14305

what is the methord u are using to shrink the masking tape

topalle

The tape is not shrinking...
I tried with hairdryer which has a small heating coil...
it blows hot air...
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Rajesh14305

it may not shrink suddenly .u try to blow hot air for some more duration

topalle

ok

Present weight of wing is 125 grams...
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Rajesh14305

 please wait 5minutes i wll post my wings photo

Rajesh14305

whats length and breadth of ur wing.weight is fair

topalle

I have alrady stated before...
Telling again...
Its 1 metre wingspan and little less than 20 cm chord ie 8 inch chord
Did you build one like that?
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Rajesh14305

her is the wing that i made out of hd foam got from lucknow

Rajesh14305

yes my wing span is 1meter by length and 18 cm by breadth.